Jack



Nov. 28, 1933. c, GQEBERT 1,936.596

JACK

Filed Nov. 11, 1952 Inventor I Elmer E EcJEhErt /2 Attorney PatentedNov. 28, 1933 i ter more Elmer C. Goebert, United States Army,l'rhiladelphia, Pa.

November ll. 1932 Serial No. M22433 @laims.

(Granted under the act of March 3, 1883, as

amended 30, 1928; 37% l). G. 757) The invention described herein may bemanufactured and used by or for the Government for governmentalpurposes, without the payment to me or" any royalty thereon.

This invention relates to ajack.

The purpose of the invention is to increase the effective bearingbetween an extensible member and its casing. A further object is toemploy the bearing member for limiting movement of the extensiblemerr'oer.

To these and other ends, the invention con sists in the construction,arrangement and combination of elements described hereinafter andpointed out in the claims forming a part of this specification.

A practical emb diment or" the lustrated in the accompanying Fig. l is alongitudinal improved jack showing th 20 position.

Fig. 2 is a similar view showing the parts telescoped, and

Fig. 3 is a sectional view on the line 33 of Fig. 2.

ihe jack consists of a tubular casing 5 having an angular offset 6 forreceiving rack teeth '7 on a tubular r cl: member 8 slidably mounted inthe casing. A spur gar 9 meshing with raclr teeth 2 mounted in a housing16 secured to 30 the lower end the A tubular guide sleeve ll is mountedfor sliding movement within the me ber 8. The sleeve 11 is of substanially length the rack member so th hen its lower rests on the disk 12closing of racl: member, upper end extend .c corresponding end of therack member. A collar 13 convenien ly threaded on the exte ded upper endof the guide sleeve has a close ing fit in the casing. The casing ispreferably formed with a countercore l: in order to provide a shoulder15 for limiting movement of the sleeve.

The interior of the sleeve ll is provided intermediate its ends with ashoulder 15 adapted to be engaged on its upper side by a nut 17 on theend of a rod 18. The lower end of the rod is secured in the disk 12.

A foot 19 is secured to the lower end of the rack member. A disk issecured to the upper end of the casing 5. The casing 5 is shown beingsecured to a plate 21 which in the particular application of theinvention represents gun carriage. In the particular employment of thejack the custoznwy ratchet mechanism is not needed and none is shown.

invention is lvise When the jack not shown in operation the parts aretelescoped as shown in Fig. 2. In operation the spur gear 9 is rotatedto lower the rack 8 and the sleeve ll may follow through the influenceof gravity. if the sleeve does not to].- low the rack, in this mannerits shoulder 16 is engaged by the nut 17 on the rod 18 at about themiddle of the stroke of the rack and is there- ;forced downwardly asindicated in Fig. l. The engagement of the collar 13 of the sleeve 2 theshoulder 15 of the casing limits the extension of the sleeve as well asthe extension purpose of extending the sleeve 11 elative 5 is toincrease the eiiective bear- 1-..g sur ace of the rack when extended.This is y shown in Fig. l, where one-half of the shoe e is -portingcontact with the fully extended rack while the collar 13 on the innerend of the sleeve bears against the upper portion of the casing 5.

The purpose in limiting the extension of the rack is to prevent the spurgear from jamming the upper end or" the rack member beyond the lasttooth.

In the reverse operation to telescope the parts, the disk 12 of thereel: engages the lower end of te sleeve to cause the sleeve to partakeof the return movement and be restored to the position shown in Fig. 2.

While in the present invention the rack is shown a downwardly extensiblemember it is to be understood that the device may be inverted so thatthe rack is upwardly extensible.

E claim:

1. In a jack, a casing, a gear carried by the casing, a rack memberslidable in the casing and driven by the gear, a tubular guide sleeveslidable in the rack member and having a shoulder in its interiorintermediate its ends, the outer end of said sleeve engageable by theouter end of the rack when the jack is it its collapsed position and theinner end of the sleeve extending beyond the inner end of the rack,means on the inner end of the sleeve bearing on the wall of the casing,means on the wall of the casing engageable with said means on the sleeveto limit extension thereof, a rod carried by the rack, and means on theinner end or the rod engageable with the shoulder of the sleeve to movethe sleeve and limit extension of the rack.

2. In a jack, a casing, a gear carried by the casing, a rack memberslidable in the casing and driven by the gear, a guide slidable relativeto and bearing on the casing and the rack, means on the casingengageable with the guide to limit extension thereof, a rod carried bythe rack and means on the rod engageable with the sleeve mid- Way of itsends to move the sleeve and limit extension of the rack.

3. In a jack, a casing, a driven member slidable in the casing andbearing thereon, a guide slidable relative to and bearing internally onboth the casing and driven member, means for limiting extension of theguide, and means on the driven member engageable with the guide after apredetermined extension of the driven member to pick up and extend theguide.

4. In a jack, a casing, a driven member mounted for extension relativeto the casing, a guide member extensible by the driven member andbearing on the casing, and means for arresting extension of said memberswhen the guide member is in engagement with approximately the inner halfof the driven member.

5. In a, jack, a casing, a driven member mounted for extension relativeto the casing and bearing thereon, and means bearing on the interiors ofthe casing and driven members for increasing the efiective bearingbetween the driven member and the casing when the driven member isextended.

- ELMER C. GOEBERT.

